Something was fishy in my last ranked game - a level 20?? People thought it was normals?

Okay so maybe I'm missing something here, and I didn't take screenshots during the game, but some weird stuff just happened.

I queued up for a Ranked game. As the changes for those chest things you can get came through, it disconnected me and I lost 3 LP which was really really annoying.

After that, I waiting for the timer to end and clicked to queue up in the SAME game lobby as before, so definitely Ranked.

I looked at op.gg before my game and it said I had a Level 20 on my team. He had no keystone and throughout the game obviously did not know how to play.

I asked everyone if this was Ranked, most said no, one said yes. Someone was "first time Jhin" and another was very adamant that they had queued for normals. Unfortunately I did not screenshot this conversation. Xin would not answer the question of what level he was.

After the game I lost LP, so it was a Ranked, and I checked LolKing. It showed the Xin as Level 13! But on League, he was Level 30, having badly lost 5 Ranked games and with nothing else in his playing history at all which I found very strange. Also it showed him as Bronze 1 in the same place LP wise as me. He did not have a full Rune page or full masteries.

I don't want to lose LP for glitches or hacks. What happened here?